Portable and flexible paving strips

ABSTRACT

The invention relates to a flexible paving strip which provides a good load-bearing paving surface but which is also particularly well adapted for transportation in the form of rolls which are readily manually laid, either as a temporary or permanent paving surface. The portable and flexible paving strip of the present invention comprises a layer of a bituminous-base binder carried and reinforced by a flexible backing and having adhered to one side of the layer an abrasion-resistant surfacing, e.g., an aggregate, and to the other side of the layer a flexible under cover bearing a layer of release agent in contact with the binder so that the undercover, when required on laying the paving strip, can be clearly separated from binder layer.

United States Patent Continuation-impart of application Ser. No.479,586, Aug. 13, 196 5, abandoned.

[54] PORTABLE AND FLEXIBLE PAVING STRIPS 3 Claims, 3 Drawing Figs.

[52] U.S.Cl. 94/7, 161/406 [51] Int. Cl. E0lc7/00 [50] Field of Search[56] References Cited UNITED STATES PATENTS 293,491 2/1884 Miner 161/831,939,004 12/1933 Fischer... 16l/406X 2,201,537 5/1940 l-licklerl61/406X 3,028,280 4/1962 Hoffman 161/406X L lla 15 M225 PrimaryExaminer.1acob L. Nackenoff Attorney-Webster B. Harpman ABSTRACT: Theinvention relates to a flexible paving strip which provides a goodload-bearing paving surface but which is also particularly well adaptedfor transportation in the form of rolls which are readily manually laid,either as a temporary or permanent paving surface. The portable andflexible paving strip of the present invention comprises a layer of abituminous-base binder carried and reinforced by a flexible backing andhaving adhered to one side of the layer an abrasion-resistant surfacing,e.g., an aggregate, and to the other side of the layer a flexible undercover bearing a layer of release agent in contact with the binder sothat the undercover, when required on laying the paving strip, can beclearly separated from binder layer.

Patented March 9,1971 3,568,579

BRIEF DESCRIPTION QF THE INVENTION There is provided by the presentinvention a portable paving strip comprising a flexible backing, abituminous-base binder forming a layer carried on and reinforced by theflexible backing, an abrasion-resistant binder-forming a layer carriedon and reinforced by the flexible backing, an abrasion-resistantsurfacing adhered to one side of the binder layer and a flexibleundercover secured to the other side of the binder layer; the flexibleundercover bearing a layer of release agent in contact with the binderto enable the undercover to be separated cleanly from the binder layer,and the thickness of the binder layer being such as to enable theabrasion-resistant surfacing to act as a load-bearing surface when thepaving strip is laid on a firm supporting surface.

The abrasion-resistant surfacing may be layer of aggregate although acontinuous surfacing such as polyethylene could be used; and it ispreferred to use a bitumen (alternatively called an asphalt) as thebinder.

Among the bitumens which may be employed in the present invention, maybe mentioned the following:

Petroleum Bitumens i. Straight run-A bitumen obtained after the finalstages of distillation of a petroleum of suitable type.

ii. Cut-Back Bitumen-A bitumen, the viscosity of which has been reducedby the addition of a volatile diluent.

iii. Blown Bitumen-A bitumen modified by blowing of air through thebitumen, under controlled temperature conditions. This process altersthe characteristics of the bitumen to give it more rubbery" properties.Bitumens so produced are known as air-blown, blown," or oxidised"grades.

iv. Colored Bitumen-A bitumen colored by addition of a proportion ofpowdered pigment. There are in existence, light colored bitumens whichare particularly suitable for coloring pigmenting.

v. Rubberized bitumen-A bitumen containing natural or synthetic rubber.The rubber which is incorporated in the bitumen by mixing at elevatedtemperatures, imparts elasticity to the bitumen and increasesflexibility at low temperatures and stability at high temperatures.

Natural Asphalt A naturally occurring mixture of bitumen and finelydivided mineral matter which is found in well defined surface deposits.Otherwise known as Lake Asphalt.

The bitumen present in Lake Asphalt is of a fairly light color and issuitable for pigmenting with powdered colored pigments to produce acolored bitumen binder. To make Lake Asphalt suitable for use as abinder in paving strips it is necessary to reduce the viscosity by theaddition of a suitable diluent, such as a petroleum distillate or coaltar distillate.

If the paving strip is to be one from which the undercover may readilybe removed, a release agent may be incorporated in the paving stripduring manufacture thereof, by application in the form of a thin film tothe undercover before the undercover is applied to the flexiblebinder-carrying backing. The undercover bearing the release agent may bea material of a nonabsorbent surface, such as metal or treated paper,e.g., metal-surfaced paper or nonabsorbent plastics sheeting and therelease agent may be applied thereon by screeding, rolling or spraying.Although the release agent acts upon the bitumen binder at the interfacewith the undercover to soften the binder, nevertheless, there is stillsufficient adhesion between the binder and the undercover to preventseparation of the undercover during handling of the paving strip.

The release agent mentioned above needs to be applied to the undercoverduring manufacture of the paving strip but a release agent maybe usedwhich can be incorporated in the material of the undercover beforehand.Thus, the undercover may consist of a material serving to lessen theadhesion between the binder and the undercover while still leaving therequisite degree of adhesion. An advantage of using treated paper isthat it separates cleanly from the binder and that it is manufactured assuch and its use as the undercover, therefore, avoids having to apply a.release agent as a step in or as a preliminary to, the manufacture ofthe paving strip itself. In the case when the aggregate layer or layerof other abrasion resistant material is dispensed with, the undercovermay be treated on both sides with the release agent in order to preventconvolutions of the strip from sticking to each other.

In accordance with the present invention, the paving strip may be formedwithout the flexible backing and the aggregate of the paving strip maybe replaced by a waterproof material such as polythene.

An embodiment of the present invention will now be described, by way ofexample only, with reference to the accompanying drawings in which:

FIG. 1. is a side elevation of the paving strip of the embodiment inflat or unrolled condition;

FIG. 2. is a like view to FIG. 1. of a modification of the paving stripthereof; and

FIG. 3. is a like view of FIG. 1. of a further modification of thepaving strip thereof.

In the three FIGS., like reference numerals indicate like arts.

In FIG. 1, the paving strip shown comprises a flexible backing strip 1impregnated with a bitumen to form a layer of binder 2. To the undersideof the backing strip 1 is secured an undercover 3 bearing a thin film 4of a release agent which although it does not prevent adhesion of theundercover to the binder layer 2 loosens the adhesion so that theundercover may be readily separated by hand. To the upper surface of thebinder, a layer 5 of aggregate has been applied so that the aggregate isfirmly retained by the binder. For clarity, part of the aggregate layerhas been omitted from FIG. 1.

In the modification of FIG. 2, the aggregate employed in FIG. 1 has beenreplaced by a layer 6 of polythene (polyethylene) and in FIG. 3, theflexible backing strip 1 has been omitted. FIG. 3 as FIG. 1 omits partof the aggregate layer in the interests of clarity. It will beunderstood that the polythene layer could also be employed in theembodiment of FIG. 3 in place of the aggregate.

We claim:

l. A portable paving strip comprising a flexible backing, abituminous-base binder forming a layer carried on and reinforced by theflexible backing, an abrasion-resistant surfacing adhered to one side ofthe binder layer and a flexible undercover secured to the other side ofthe binder layer; the flexible undercover bearing a layer of releaseagent in contact with the binder to enable the undercover to beseparated cleanly from the binder layer, and the thickness of the binderlayer being such as to enable the abrasion-resistant surfacing to act asa load-bearing surface when the paving strip is laid on a firmsupporting surface.

2. A portable paving strip as claimed in claim ll, wherein theabrasion-resistant surfacing consists of a layer of aggregate.

3. A portable paving strip as claimed in claim 2, wherein the bituminousbinder is a bitumen.

1. A portable paving strip comprising a flexible backing, abituminous-base binder forming a layer carried on and reinforced by theflexible backing, an abrasion-resistant surfacing adhered to one side ofthe binder layer and a flexible undercover secured to the other side ofthe binder layer; the flexible undercover bearing a layer of releaseagent in contact with the binder to enable the undercover to beseparated cleanly from the binder layer, and the thickness of the binderlayer being such as to enable the abrasion-resistant surfacing to act asa load-bearing surface when the paving strip is laid on a firmsupporting surface.
 2. A portable paving strip as claimed in claim 1,wherein the abrasion-resistant surfacing consists of a layer ofaggregate.
 3. A portable paving strip as claimed in claim 2, wherein thebituminous binder is a bitumen.